A diesel fuel filter is used with a diesel fuel supply apparatus in order to filter diesel fuel stored in a fuel tank and supply filtered diesel fuel to a diesel engine.
The diesel fuel filter may filter impurities included in diesel fuel and separate moisture therefrom, and discharge the moisture to the outside. In addition, the diesel fuel filter may heat diesel fuel to prevent coagulation and supply the diesel fuel to the diesel engine. Thus, problems caused by impurities may be prevented in advance.
In order to maintain diesel fuel at an appropriate temperature, the diesel fuel filter includes a filter heater. In addition, a filter heater relay supplying power from a battery to the filter heater or cutting off supply of power is provided between the battery and the filter heater.
If the filter heater relay is stuck open, power cannot be supplied to the filter heater, making it impossible to increase a temperature of diesel fuel to an appropriate temperature during cold weather, which may degrade a cold start of the diesel engine during the winter.
If the filter heater relay is stuck closed, power may continue to be supplied to the filter heater, making a temperature of diesel fuel exceed an appropriate temperature during the summer, damaging the diesel fuel filter.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.